#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/hash.h>
+#include <linux/rbtree.h>
/*
- * feel free to try other values :-). read_expire value is the timeout for
- * reads, our goal is to start a request "around" the time when it expires.
- * fifo_batch is how many steps along the sorted list we will take when the
- * front fifo request expires.
+ * See Documentation/deadline-iosched.txt
*/
-static int read_expire = HZ / 2; /* 500ms start timeout */
-static int fifo_batch = 16;
-static int seek_cost = 16; /* seek is 16 times more expensive */
+static int read_expire = HZ / 2; /* max time before a read is submitted. */
+static int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
+static int writes_starved = 2; /* max times reads can starve a write */
+static int fifo_batch = 16; /* # of sequential requests treated as one
+ by the above parameters. For throughput. */
-/*
- * how many times reads are allowed to starve writes
- */
-static int writes_starved = 2;
-
-static const int deadline_hash_shift = 8;
+static const int deadline_hash_shift = 10;
#define DL_HASH_BLOCK(sec) ((sec) >> 3)
#define DL_HASH_FN(sec) (hash_long(DL_HASH_BLOCK((sec)), deadline_hash_shift))
#define DL_HASH_ENTRIES (1 << deadline_hash_shift)
+#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors)
+#define list_entry_hash(ptr) list_entry((ptr), struct deadline_rq, hash)
+#define ON_HASH(drq) (drq)->hash_valid_count
#define DL_INVALIDATE_HASH(dd) \
do { \
/*
* run time data
*/
- struct list_head sort_list[2]; /* sorted listed */
- struct list_head read_fifo; /* fifo list */
+
+ /*
+ * requests (deadline_rq s) are present on both sort_list and fifo_list
+ */
+ struct rb_root sort_list[2];
+ struct list_head fifo_list[2];
+
+ /*
+ * next in sort order. read, write or both are NULL
+ */
+ struct deadline_rq *next_drq[2];
struct list_head *dispatch; /* driver dispatch queue */
struct list_head *hash; /* request hash */
- sector_t last_sector; /* last sector sent to drive */
unsigned long hash_valid_count; /* barrier hash count */
- unsigned int starved; /* writes starved */
+ unsigned int batching; /* number of sequential requests made */
+ sector_t last_sector; /* head position */
+ unsigned int starved; /* times reads have starved writes */
/*
* settings that change how the i/o scheduler behaves
*/
- unsigned int fifo_batch;
- unsigned long read_expire;
- unsigned int seek_cost;
- unsigned int writes_starved;
+ int fifo_expire[2];
+ int fifo_batch;
+ int writes_starved;
+ int front_merges;
};
/*
* pre-request data.
*/
struct deadline_rq {
- struct list_head fifo;
+ /*
+ * rbtree index, key is the starting offset
+ */
+ struct rb_node rb_node;
+ sector_t rb_key;
+
+ struct request *request;
+
+ /*
+ * request hash, key is the ending offset (for back merge lookup)
+ */
struct list_head hash;
unsigned long hash_valid_count;
- struct request *request;
+
+ /*
+ * expire fifo
+ */
+ struct list_head fifo;
unsigned long expires;
};
#define RQ_DATA(rq) ((struct deadline_rq *) (rq)->elevator_private)
/*
- * rq hash
+ * the back merge hash support functions
*/
-static inline void __deadline_del_rq_hash(struct deadline_rq *drq)
+static inline void __deadline_del_drq_hash(struct deadline_rq *drq)
{
drq->hash_valid_count = 0;
list_del_init(&drq->hash);
}
-#define ON_HASH(drq) (drq)->hash_valid_count
-static inline void deadline_del_rq_hash(struct deadline_rq *drq)
+static inline void deadline_del_drq_hash(struct deadline_rq *drq)
{
if (ON_HASH(drq))
- __deadline_del_rq_hash(drq);
+ __deadline_del_drq_hash(drq);
}
static inline void
-deadline_add_rq_hash(struct deadline_data *dd, struct deadline_rq *drq)
+deadline_add_drq_hash(struct deadline_data *dd, struct deadline_rq *drq)
{
struct request *rq = drq->request;
BUG_ON(ON_HASH(drq));
drq->hash_valid_count = dd->hash_valid_count;
- list_add(&drq->hash, &dd->hash[DL_HASH_FN(rq->sector +rq->nr_sectors)]);
+ list_add(&drq->hash, &dd->hash[DL_HASH_FN(rq_hash_key(rq))]);
}
-#define list_entry_hash(ptr) list_entry((ptr), struct deadline_rq, hash)
static struct request *
-deadline_find_hash(struct deadline_data *dd, sector_t offset)
+deadline_find_drq_hash(struct deadline_data *dd, sector_t offset)
{
struct list_head *hash_list = &dd->hash[DL_HASH_FN(offset)];
struct list_head *entry, *next = hash_list->next;
- struct deadline_rq *drq;
- struct request *rq = NULL;
while ((entry = next) != hash_list) {
+ struct deadline_rq *drq = list_entry_hash(entry);
+ struct request *__rq = drq->request;
+
next = entry->next;
- drq = list_entry_hash(entry);
-
- BUG_ON(!drq->hash_valid_count);
+ BUG_ON(!ON_HASH(drq));
- if (!rq_mergeable(drq->request)
+ if (!rq_mergeable(__rq)
|| drq->hash_valid_count != dd->hash_valid_count) {
- __deadline_del_rq_hash(drq);
+ __deadline_del_drq_hash(drq);
continue;
}
- if (drq->request->sector + drq->request->nr_sectors == offset) {
- rq = drq->request;
- break;
- }
+ if (rq_hash_key(__rq) == offset)
+ return __rq;
}
- return rq;
+ return NULL;
}
-static sector_t deadline_get_last_sector(struct deadline_data *dd)
+/*
+ * rb tree support functions
+ */
+#define RB_NONE (2)
+#define RB_EMPTY(root) ((root)->rb_node == NULL)
+#define ON_RB(node) ((node)->rb_color != RB_NONE)
+#define RB_CLEAR(node) ((node)->rb_color = RB_NONE)
+#define rb_entry_drq(node) rb_entry((node), struct deadline_rq, rb_node)
+#define DRQ_RB_ROOT(dd, drq) (&(dd)->sort_list[rq_data_dir((drq)->request)])
+#define rq_rb_key(rq) (rq)->sector
+
+static struct deadline_rq *
+__deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
{
- sector_t last_sec = dd->last_sector;
+ struct rb_node **p = &DRQ_RB_ROOT(dd, drq)->rb_node;
+ struct rb_node *parent = NULL;
+ struct deadline_rq *__drq;
+
+ while (*p) {
+ parent = *p;
+ __drq = rb_entry_drq(parent);
+
+ if (drq->rb_key < __drq->rb_key)
+ p = &(*p)->rb_left;
+ else if (drq->rb_key > __drq->rb_key)
+ p = &(*p)->rb_right;
+ else
+ return __drq;
+ }
+
+ rb_link_node(&drq->rb_node, parent, p);
+ return 0;
+}
+
+static int
+deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
+{
+ struct deadline_rq *__alias;
+
+ drq->rb_key = rq_rb_key(drq->request);
+
+ __alias = __deadline_add_drq_rb(dd, drq);
+ if (!__alias) {
+ rb_insert_color(&drq->rb_node, DRQ_RB_ROOT(dd, drq));
+ return 0;
+ }
/*
- * if dispatch is non-empty, disregard last_sector and check last one
+ * this should not typically happen, but if it does simply chain
+ * the two requests. then they will be moved to the dispatch list
+ * at the same time
*/
- if (!list_empty(dd->dispatch)) {
- struct request *__rq = list_entry_rq(dd->dispatch->prev);
+ list_add(&drq->request->queuelist, &__alias->request->queuelist);
+ return 1;
+}
+
+static inline void
+deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
+{
+ const int data_dir = rq_data_dir(drq->request);
+
+ if (dd->next_drq[data_dir] == drq) {
+ struct rb_node *rbnext = rb_next(&drq->rb_node);
+
+ dd->next_drq[data_dir] = NULL;
+ if (rbnext)
+ dd->next_drq[data_dir] = rb_entry_drq(rbnext);
+ }
+
+ if (ON_RB(&drq->rb_node)) {
+ rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq));
+ RB_CLEAR(&drq->rb_node);
+ }
+}
- last_sec = __rq->sector + __rq->nr_sectors;
+static struct request *
+deadline_find_drq_rb(struct deadline_data *dd, sector_t sector, int data_dir)
+{
+ struct rb_node *n = dd->sort_list[data_dir].rb_node;
+ struct deadline_rq *drq;
+
+ while (n) {
+ drq = rb_entry_drq(n);
+
+ if (sector < drq->rb_key)
+ n = n->rb_left;
+ else if (sector > drq->rb_key)
+ n = n->rb_right;
+ else
+ return drq->request;
}
- return last_sec;
+ return NULL;
+}
+
+/*
+ * deadline_find_first_drq finds the first (lowest sector numbered) request
+ * for the specified data_dir. Used to sweep back to the start of the disk
+ * (1-way elevator) after we process the last (highest sector) request.
+ */
+static struct deadline_rq *
+deadline_find_first_drq(struct deadline_data *dd, int data_dir)
+{
+ struct rb_node *n = dd->sort_list[data_dir].rb_node;
+
+ for (;;) {
+ if (n->rb_left == NULL)
+ return rb_entry_drq(n);
+
+ n = n->rb_left;
+ }
+}
+
+/*
+ * add drq to rbtree and fifo
+ */
+static inline void
+deadline_add_request(struct deadline_data *dd, struct deadline_rq *drq)
+{
+ const int data_dir = rq_data_dir(drq->request);
+
+ if (!deadline_add_drq_rb(dd, drq)) {
+ /*
+ * set expire time (only used for reads) and add to fifo list
+ */
+ drq->expires = jiffies + dd->fifo_expire[data_dir];
+ list_add_tail(&drq->fifo, &dd->fifo_list[data_dir]);
+ }
+}
+
+/*
+ * remove rq from rbtree, fifo, and hash
+ */
+static void deadline_remove_request(request_queue_t *q, struct request *rq)
+{
+ struct deadline_rq *drq = RQ_DATA(rq);
+
+ if (drq) {
+ struct deadline_data *dd = q->elevator.elevator_data;
+
+ list_del_init(&drq->fifo);
+ deadline_del_drq_hash(drq);
+ deadline_del_drq_rb(dd, drq);
+ }
+
+ list_del_init(&rq->queuelist);
}
static int
deadline_merge(request_queue_t *q, struct list_head **insert, struct bio *bio)
{
struct deadline_data *dd = q->elevator.elevator_data;
- const int data_dir = bio_data_dir(bio);
- struct list_head *entry, *sort_list;
struct request *__rq;
- int ret = ELEVATOR_NO_MERGE;
+ int ret;
/*
* try last_merge to avoid going to hash
*/
ret = elv_try_last_merge(q, bio);
if (ret != ELEVATOR_NO_MERGE) {
- *insert = q->last_merge;
- goto out;
+ __rq = list_entry_rq(q->last_merge);
+ goto out_insert;
}
/*
* see if the merge hash can satisfy a back merge
*/
- if ((__rq = deadline_find_hash(dd, bio->bi_sector))) {
+ __rq = deadline_find_drq_hash(dd, bio->bi_sector);
+ if (__rq) {
BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector);
if (elv_rq_merge_ok(__rq, bio)) {
- *insert = &__rq->queuelist;
ret = ELEVATOR_BACK_MERGE;
goto out;
}
}
/*
- * scan list from back to find insertion point.
+ * check for front merge
*/
- entry = sort_list = &dd->sort_list[data_dir];
- while ((entry = entry->prev) != sort_list) {
- __rq = list_entry_rq(entry);
+ if (dd->front_merges) {
+ sector_t rb_key = bio->bi_sector + bio_sectors(bio);
- BUG_ON(__rq->flags & REQ_STARTED);
+ __rq = deadline_find_drq_rb(dd, rb_key, bio_data_dir(bio));
+ if (__rq) {
+ BUG_ON(rb_key != rq_rb_key(__rq));
- if (!(__rq->flags & REQ_CMD))
- continue;
-
- /*
- * it's not necessary to break here, and in fact it could make
- * us loose a front merge. emperical evidence shows this to
- * be a big waste of cycles though, so quit scanning
- */
- if (!*insert && bio_rq_in_between(bio, __rq, sort_list)) {
- *insert = &__rq->queuelist;
- break;
- }
-
- if (__rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER))
- break;
-
- /*
- * checking for a front merge, hash will miss those
- */
- if (__rq->sector - bio_sectors(bio) == bio->bi_sector) {
- ret = elv_try_merge(__rq, bio);
- if (ret != ELEVATOR_NO_MERGE) {
- *insert = &__rq->queuelist;
- break;
+ if (elv_rq_merge_ok(__rq, bio)) {
+ ret = ELEVATOR_FRONT_MERGE;
+ goto out;
}
}
}
- /*
- * no insertion point found, check the very front
- */
- if (!*insert && !list_empty(sort_list)) {
- __rq = list_entry_rq(sort_list->next);
-
- if (bio->bi_sector + bio_sectors(bio) < __rq->sector &&
- bio->bi_sector > deadline_get_last_sector(dd))
- *insert = sort_list;
- }
-
+ return ELEVATOR_NO_MERGE;
out:
+ q->last_merge = &__rq->queuelist;
+out_insert:
+ *insert = &__rq->queuelist;
return ret;
}
struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(req);
- deadline_del_rq_hash(drq);
- deadline_add_rq_hash(dd, drq);
+ /*
+ * hash always needs to be repositioned, key is end sector
+ */
+ deadline_del_drq_hash(drq);
+ deadline_add_drq_hash(dd, drq);
+
+ /*
+ * if the merge was a front merge, we need to reposition request
+ */
+ if (rq_rb_key(req) != drq->rb_key) {
+ deadline_del_drq_rb(dd, drq);
+ deadline_add_drq_rb(dd, drq);
+ }
q->last_merge = &req->queuelist;
}
static void
-deadline_merge_request(request_queue_t *q, struct request *req, struct request *next)
+deadline_merged_requests(request_queue_t *q, struct request *req,
+ struct request *next)
{
struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(req);
BUG_ON(!drq);
BUG_ON(!dnext);
- deadline_del_rq_hash(drq);
- deadline_add_rq_hash(dd, drq);
+ /*
+ * reposition drq (this is the merged request) in hash, and in rbtree
+ * in case of a front merge
+ */
+ deadline_del_drq_hash(drq);
+ deadline_add_drq_hash(dd, drq);
+
+ if (rq_rb_key(req) != drq->rb_key) {
+ deadline_del_drq_rb(dd, drq);
+ deadline_add_drq_rb(dd, drq);
+ }
/*
- * if dnext expires before drq, assign it's expire time to drq
+ * if dnext expires before drq, assign its expire time to drq
* and move into dnext position (dnext will be deleted) in fifo
*/
if (!list_empty(&drq->fifo) && !list_empty(&dnext->fifo)) {
drq->expires = dnext->expires;
}
}
+
+ /*
+ * kill knowledge of next, this one is a goner
+ */
+ deadline_remove_request(q, next);
}
/*
- * move request from sort list to dispatch queue. maybe remove from rq hash
- * here too?
+ * move request from sort list to dispatch queue.
*/
static inline void
-deadline_move_to_dispatch(struct deadline_data *dd, struct request *rq)
+deadline_move_to_dispatch(struct deadline_data *dd, struct deadline_rq *drq)
{
- struct deadline_rq *drq = RQ_DATA(rq);
-
- list_move_tail(&rq->queuelist, dd->dispatch);
+ deadline_del_drq_rb(dd, drq);
list_del_init(&drq->fifo);
+ list_add_tail(&drq->request->queuelist, dd->dispatch);
}
/*
- * move along sort list and move entries to dispatch queue, starting from rq
+ * move an entry to dispatch queue
*/
-static void deadline_move_requests(struct deadline_data *dd, struct request *rq)
+static void
+deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq)
{
- struct list_head *sort_head = &dd->sort_list[rq_data_dir(rq)];
- sector_t last_sec = deadline_get_last_sector(dd);
- int batch_count = dd->fifo_batch;
-
- do {
- struct list_head *nxt = rq->queuelist.next;
- int this_rq_cost;
-
- /*
- * take it off the sort and fifo list, move
- * to dispatch queue
- */
- deadline_move_to_dispatch(dd, rq);
-
- /*
- * if this is the last entry, don't bother doing accounting
- */
- if (nxt == sort_head)
- break;
+ const int data_dir = rq_data_dir(drq->request);
+ struct rb_node *rbnext = rb_next(&drq->rb_node);
- this_rq_cost = dd->seek_cost;
- if (rq->sector == last_sec)
- this_rq_cost = (rq->nr_sectors + 255) >> 8;
+ dd->next_drq[READ] = NULL;
+ dd->next_drq[WRITE] = NULL;
- batch_count -= this_rq_cost;
- if (batch_count <= 0)
- break;
+ if (rbnext)
+ dd->next_drq[data_dir] = rb_entry_drq(rbnext);
+
+ dd->last_sector = drq->request->sector + drq->request->nr_sectors;
- last_sec = rq->sector + rq->nr_sectors;
- rq = list_entry_rq(nxt);
- } while (1);
+ /*
+ * take it off the sort and fifo list, move
+ * to dispatch queue
+ */
+ deadline_move_to_dispatch(dd, drq);
}
+#define list_entry_fifo(ptr) list_entry((ptr), struct deadline_rq, fifo)
+
/*
- * returns 0 if there are no expired reads on the fifo, 1 otherwise
+ * deadline_check_fifo returns 0 if there are no expired reads on the fifo,
+ * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
*/
-#define list_entry_fifo(ptr) list_entry((ptr), struct deadline_rq, fifo)
-static inline int deadline_check_fifo(struct deadline_data *dd)
+static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
{
- if (!list_empty(&dd->read_fifo)) {
- struct deadline_rq *drq = list_entry_fifo(dd->read_fifo.next);
+ struct deadline_rq *drq = list_entry_fifo(dd->fifo_list[ddir].next);
- /*
- * drq is expired!
- */
- if (time_after(jiffies, drq->expires))
- return 1;
- }
+ /*
+ * drq is expired!
+ */
+ if (time_after(jiffies, drq->expires))
+ return 1;
return 0;
}
-static struct request *deadline_next_request(request_queue_t *q)
+/*
+ * deadline_dispatch_requests selects the best request according to
+ * read/write expire, fifo_batch, etc
+ */
+static int deadline_dispatch_requests(struct deadline_data *dd)
{
- struct deadline_data *dd = q->elevator.elevator_data;
+ const int reads = !list_empty(&dd->fifo_list[READ]);
+ const int writes = !list_empty(&dd->fifo_list[WRITE]);
struct deadline_rq *drq;
- struct list_head *nxt;
- struct request *rq;
- int writes;
+ int data_dir, other_dir;
/*
- * if still requests on the dispatch queue, just grab the first one
+ * batches are currently reads XOR writes
*/
- if (!list_empty(&q->queue_head)) {
-dispatch:
- rq = list_entry_rq(q->queue_head.next);
- dd->last_sector = rq->sector + rq->nr_sectors;
- return rq;
- }
+ drq = NULL;
+
+ if (dd->next_drq[READ])
+ drq = dd->next_drq[READ];
- writes = !list_empty(&dd->sort_list[WRITE]);
+ if (dd->next_drq[WRITE])
+ drq = dd->next_drq[WRITE];
+
+ if (drq) {
+ /* we have a "next request" */
+
+ if (dd->last_sector != drq->request->sector)
+ /* end the batch on a non sequential request */
+ dd->batching += dd->fifo_batch;
+
+ if (dd->batching < dd->fifo_batch)
+ /* we are still entitled to batch */
+ goto dispatch_request;
+ }
/*
- * if we have expired entries on the fifo list, move some to dispatch
+ * at this point we are not running a batch. select the appropriate
+ * data direction (read / write)
*/
- if (deadline_check_fifo(dd)) {
- if (writes && (dd->starved++ >= dd->writes_starved))
- goto dispatch_writes;
- nxt = dd->read_fifo.next;
- drq = list_entry_fifo(nxt);
- deadline_move_requests(dd, drq->request);
- goto dispatch;
- }
+ if (reads) {
+ BUG_ON(RB_EMPTY(&dd->sort_list[READ]));
- if (!list_empty(&dd->sort_list[READ])) {
if (writes && (dd->starved++ >= dd->writes_starved))
goto dispatch_writes;
- nxt = dd->sort_list[READ].next;
- deadline_move_requests(dd, list_entry_rq(nxt));
- goto dispatch;
+ data_dir = READ;
+ other_dir = WRITE;
+
+ goto dispatch_find_request;
}
/*
- * either there are no reads expired or on sort list, or the reads
- * have starved writes for too long. dispatch some writes
+ * there are either no reads or writes have been starved
*/
+
if (writes) {
dispatch_writes:
- nxt = dd->sort_list[WRITE].next;
- deadline_move_requests(dd, list_entry_rq(nxt));
+ BUG_ON(RB_EMPTY(&dd->sort_list[WRITE]));
+
dd->starved = 0;
- goto dispatch;
+
+ data_dir = WRITE;
+ other_dir = READ;
+
+ goto dispatch_find_request;
}
- BUG_ON(!list_empty(&dd->sort_list[READ]));
- BUG_ON(writes);
+ return 0;
+
+dispatch_find_request:
+ /*
+ * we are not running a batch, find best request for selected data_dir
+ */
+ if (deadline_check_fifo(dd, data_dir)) {
+ /* An expired request exists - satisfy it */
+ dd->batching = 0;
+ drq = list_entry_fifo(dd->fifo_list[data_dir].next);
+
+ } else if (dd->next_drq[data_dir]) {
+ /*
+ * The last req was the same dir and we have a next request in
+ * sort order. No expired requests so continue on from here.
+ */
+ drq = dd->next_drq[data_dir];
+ } else {
+ /*
+ * The last req was the other direction or we have run out of
+ * higher-sectored requests. Go back to the lowest sectored
+ * request (1 way elevator) and start a new batch.
+ */
+ dd->batching = 0;
+ drq = deadline_find_first_drq(dd, data_dir);
+ }
+
+dispatch_request:
+ /*
+ * drq is the selected appropriate request.
+ */
+ dd->batching++;
+ deadline_move_request(dd, drq);
+
+ return 1;
+}
+
+static struct request *deadline_next_request(request_queue_t *q)
+{
+ struct deadline_data *dd = q->elevator.elevator_data;
+ struct request *rq;
+
+ /*
+ * if there are still requests on the dispatch queue, grab the first one
+ */
+ if (!list_empty(dd->dispatch)) {
+dispatch:
+ rq = list_entry_rq(dd->dispatch->next);
+ return rq;
+ }
+
+ if (deadline_dispatch_requests(dd))
+ goto dispatch;
+
return NULL;
}
static void
-deadline_add_request(request_queue_t *q, struct request *rq, struct list_head *insert_here)
+deadline_insert_request(request_queue_t *q, struct request *rq,
+ struct list_head *insert_here)
{
struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(rq);
- const int data_dir = rq_data_dir(rq);
- /*
- * flush hash on barrier insert, as not to allow merges before a
- * barrier.
- */
if (unlikely(rq->flags & REQ_HARDBARRIER)) {
DL_INVALIDATE_HASH(dd);
q->last_merge = NULL;
}
- /*
- * add to sort list
- */
- if (!insert_here)
- insert_here = dd->sort_list[data_dir].prev;
+ if (unlikely(!blk_fs_request(rq))) {
+ if (!insert_here)
+ insert_here = dd->dispatch->prev;
- list_add(&rq->queuelist, insert_here);
-
- if (unlikely(!(rq->flags & REQ_CMD)))
+ list_add(&rq->queuelist, insert_here);
return;
+ }
if (rq_mergeable(rq)) {
- deadline_add_rq_hash(dd, drq);
+ deadline_add_drq_hash(dd, drq);
if (!q->last_merge)
q->last_merge = &rq->queuelist;
}
- if (data_dir == READ) {
- /*
- * set expire time and add to fifo list
- */
- drq->expires = jiffies + dd->read_expire;
- list_add_tail(&drq->fifo, &dd->read_fifo);
- }
-}
-
-static void deadline_remove_request(request_queue_t *q, struct request *rq)
-{
- struct deadline_rq *drq = RQ_DATA(rq);
-
- if (drq) {
- list_del_init(&drq->fifo);
- deadline_del_rq_hash(drq);
- }
+ deadline_add_request(dd, drq);
}
static int deadline_queue_empty(request_queue_t *q)
{
struct deadline_data *dd = q->elevator.elevator_data;
- if (!list_empty(&dd->sort_list[WRITE]) ||
- !list_empty(&dd->sort_list[READ]) ||
- !list_empty(&q->queue_head))
+ if (!list_empty(&dd->fifo_list[WRITE])
+ || !list_empty(&dd->fifo_list[READ])
+ || !list_empty(dd->dispatch))
return 0;
- BUG_ON(!list_empty(&dd->read_fifo));
return 1;
}
-static struct list_head *
-deadline_get_sort_head(request_queue_t *q, struct request *rq)
+static struct request *
+deadline_former_request(request_queue_t *q, struct request *rq)
{
- struct deadline_data *dd = q->elevator.elevator_data;
+ struct deadline_rq *drq = RQ_DATA(rq);
+ struct rb_node *rbprev = rb_prev(&drq->rb_node);
+
+ if (rbprev)
+ return rb_entry_drq(rbprev)->request;
+
+ return NULL;
+}
+
+static struct request *
+deadline_latter_request(request_queue_t *q, struct request *rq)
+{
+ struct deadline_rq *drq = RQ_DATA(rq);
+ struct rb_node *rbnext = rb_next(&drq->rb_node);
+
+ if (rbnext)
+ return rb_entry_drq(rbnext)->request;
- return &dd->sort_list[rq_data_dir(rq)];
+ return NULL;
}
static void deadline_exit(request_queue_t *q, elevator_t *e)
struct request *rq;
int i;
- BUG_ON(!list_empty(&dd->read_fifo));
- BUG_ON(!list_empty(&dd->sort_list[READ]));
- BUG_ON(!list_empty(&dd->sort_list[WRITE]));
+ BUG_ON(!list_empty(&dd->fifo_list[READ]));
+ BUG_ON(!list_empty(&dd->fifo_list[WRITE]));
for (i = READ; i <= WRITE; i++) {
struct request_list *rl = &q->rq[i];
- struct list_head *entry = &rl->free;
+ struct list_head *entry;
- if (list_empty(&rl->free))
- continue;
-
- while ((entry = entry->next) != &rl->free) {
+ list_for_each(entry, &rl->free) {
rq = list_entry_rq(entry);
if ((drq = RQ_DATA(rq)) == NULL)
for (i = 0; i < DL_HASH_ENTRIES; i++)
INIT_LIST_HEAD(&dd->hash[i]);
- INIT_LIST_HEAD(&dd->read_fifo);
- INIT_LIST_HEAD(&dd->sort_list[READ]);
- INIT_LIST_HEAD(&dd->sort_list[WRITE]);
+ INIT_LIST_HEAD(&dd->fifo_list[READ]);
+ INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
+ dd->sort_list[READ] = RB_ROOT;
+ dd->sort_list[WRITE] = RB_ROOT;
dd->dispatch = &q->queue_head;
- dd->fifo_batch = fifo_batch;
- dd->read_expire = read_expire;
- dd->seek_cost = seek_cost;
+ dd->fifo_expire[READ] = read_expire;
+ dd->fifo_expire[WRITE] = write_expire;
dd->hash_valid_count = 1;
dd->writes_starved = writes_starved;
+ dd->front_merges = 1;
+ dd->fifo_batch = fifo_batch;
e->elevator_data = dd;
for (i = READ; i <= WRITE; i++) {
struct request_list *rl = &q->rq[i];
- struct list_head *entry = &rl->free;
+ struct list_head *entry;
- if (list_empty(&rl->free))
- continue;
-
- while ((entry = entry->next) != &rl->free) {
+ list_for_each(entry, &rl->free) {
rq = list_entry_rq(entry);
drq = kmem_cache_alloc(drq_pool, GFP_KERNEL);
memset(drq, 0, sizeof(*drq));
INIT_LIST_HEAD(&drq->fifo);
INIT_LIST_HEAD(&drq->hash);
+ RB_CLEAR(&drq->rb_node);
drq->request = rq;
rq->elevator_private = drq;
}
return ret;
}
+/*
+ * sysfs parts below
+ */
+struct deadline_fs_entry {
+ struct attribute attr;
+ ssize_t (*show)(struct deadline_data *, char *);
+ ssize_t (*store)(struct deadline_data *, const char *);
+};
+
+static ssize_t
+deadline_var_show(unsigned int var, char *page)
+{
+ return sprintf(page, "%d\n", var);
+}
+
+static ssize_t
+deadline_var_store(unsigned int *var, const char *page)
+{
+ char *p = (char *) page;
+ int ret = strlen(p);
+
+ *var = simple_strtoul(p, &p, 10);
+ return ret;
+}
+
+#define SHOW_FUNCTION(__FUNC, __VAR) \
+static ssize_t __FUNC(struct deadline_data *dd, char *page) \
+{ \
+ return deadline_var_show(__VAR, (page)); \
+}
+SHOW_FUNCTION(deadline_readexpire_show, dd->fifo_expire[READ]);
+SHOW_FUNCTION(deadline_writeexpire_show, dd->fifo_expire[WRITE]);
+SHOW_FUNCTION(deadline_writesstarved_show, dd->writes_starved);
+SHOW_FUNCTION(deadline_frontmerges_show, dd->front_merges);
+SHOW_FUNCTION(deadline_fifobatch_show, dd->fifo_batch);
+#undef SHOW_FUNCTION
+
+#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX) \
+static ssize_t __FUNC(struct deadline_data *dd, const char *page) \
+{ \
+ int ret = deadline_var_store(__PTR, (page)); \
+ if (*(__PTR) < (MIN)) \
+ *(__PTR) = (MIN); \
+ else if (*(__PTR) > (MAX)) \
+ *(__PTR) = (MAX); \
+ return ret; \
+}
+STORE_FUNCTION(deadline_readexpire_store, &dd->fifo_expire[READ], 0, INT_MAX);
+STORE_FUNCTION(deadline_writeexpire_store, &dd->fifo_expire[WRITE], 0, INT_MAX);
+STORE_FUNCTION(deadline_writesstarved_store, &dd->writes_starved, INT_MIN, INT_MAX);
+STORE_FUNCTION(deadline_frontmerges_store, &dd->front_merges, 0, 1);
+STORE_FUNCTION(deadline_fifobatch_store, &dd->fifo_batch, 0, INT_MAX);
+#undef STORE_FUNCTION
+
+static struct deadline_fs_entry deadline_readexpire_entry = {
+ .attr = {.name = "read_expire", .mode = S_IRUGO | S_IWUSR },
+ .show = deadline_readexpire_show,
+ .store = deadline_readexpire_store,
+};
+static struct deadline_fs_entry deadline_writeexpire_entry = {
+ .attr = {.name = "write_expire", .mode = S_IRUGO | S_IWUSR },
+ .show = deadline_writeexpire_show,
+ .store = deadline_writeexpire_store,
+};
+static struct deadline_fs_entry deadline_writesstarved_entry = {
+ .attr = {.name = "writes_starved", .mode = S_IRUGO | S_IWUSR },
+ .show = deadline_writesstarved_show,
+ .store = deadline_writesstarved_store,
+};
+static struct deadline_fs_entry deadline_frontmerges_entry = {
+ .attr = {.name = "front_merges", .mode = S_IRUGO | S_IWUSR },
+ .show = deadline_frontmerges_show,
+ .store = deadline_frontmerges_store,
+};
+static struct deadline_fs_entry deadline_fifobatch_entry = {
+ .attr = {.name = "fifo_batch", .mode = S_IRUGO | S_IWUSR },
+ .show = deadline_fifobatch_show,
+ .store = deadline_fifobatch_store,
+};
+
+static struct attribute *default_attrs[] = {
+ &deadline_readexpire_entry.attr,
+ &deadline_writeexpire_entry.attr,
+ &deadline_writesstarved_entry.attr,
+ &deadline_frontmerges_entry.attr,
+ &deadline_fifobatch_entry.attr,
+ NULL,
+};
+
+#define to_deadline(atr) container_of((atr), struct deadline_fs_entry, attr)
+
+static ssize_t
+deadline_attr_show(struct kobject *kobj, struct attribute *attr, char *page,
+ size_t length, loff_t offset)
+{
+ elevator_t *e = container_of(kobj, elevator_t, kobj);
+ struct deadline_fs_entry *entry = to_deadline(attr);
+
+ if (!entry->show)
+ return 0;
+ if (offset)
+ return 0;
+
+ return entry->show(e->elevator_data, page);
+}
+
+static ssize_t
+deadline_attr_store(struct kobject *kobj, struct attribute *attr,
+ const char *page, size_t length, loff_t offset)
+{
+ elevator_t *e = container_of(kobj, elevator_t, kobj);
+ struct deadline_fs_entry *entry = to_deadline(attr);
+
+ if (!entry->store)
+ return -EINVAL;
+ if (offset)
+ return 0;
+
+ return entry->store(e->elevator_data, page);
+}
+
+static struct sysfs_ops deadline_sysfs_ops = {
+ .show = deadline_attr_show,
+ .store = deadline_attr_store,
+};
+
+struct kobj_type deadline_ktype = {
+ .sysfs_ops = &deadline_sysfs_ops,
+ .default_attrs = default_attrs,
+};
+
static int __init deadline_slab_setup(void)
{
drq_pool = kmem_cache_create("deadline_drq", sizeof(struct deadline_rq),
- 0, SLAB_HWCACHE_ALIGN, NULL, NULL);
+ 0, 0, NULL, NULL);
if (!drq_pool)
panic("deadline: can't init slab pool\n");
elevator_t iosched_deadline = {
.elevator_merge_fn = deadline_merge,
.elevator_merged_fn = deadline_merged_request,
- .elevator_merge_req_fn = deadline_merge_request,
+ .elevator_merge_req_fn = deadline_merged_requests,
.elevator_next_req_fn = deadline_next_request,
- .elevator_add_req_fn = deadline_add_request,
+ .elevator_add_req_fn = deadline_insert_request,
.elevator_remove_req_fn = deadline_remove_request,
.elevator_queue_empty_fn = deadline_queue_empty,
- .elevator_get_sort_head_fn = deadline_get_sort_head,
+ .elevator_former_req_fn = deadline_former_request,
+ .elevator_latter_req_fn = deadline_latter_request,
.elevator_init_fn = deadline_init,
.elevator_exit_fn = deadline_exit,
+
+ .elevator_ktype = &deadline_ktype,
};
EXPORT_SYMBOL(iosched_deadline);
projects / history.git / commitdiff